The present invention relates to the manufacture of smokers' products, and in one embodiment is particularly concerned with the manufacture of cigarette filter rods. More specifically along these lines, the invention is directed to the integrated monitoring, diagnosis and correction of possible faults in machines for such manufacture.
In the tobacco processing industry the manufacture of smokers' products is carried out with high-speed machines that produce large quantities of products in unit time. For example, a machine for producing cigarette filter rods from a continuous tow of filamentary material might normally process the tow at speeds of around 200-400 meters per minute to produce filter rods at a rate of 4000 per minute. Due to the high speed at which they operate and the various functions that must be performed in order to carry out such a manufacturing process, these machines tend to have a fairly high level of complexity. It is thus inevitable that conditions such as wear, misalignment or failure of components of the machine can lead to situations which will require the manufacturing operation to be stopped and the source of a problem repaired.
Systems are known in which the machine is automatically halted when a malfunction is detected during its operation. One example of such a system is shown in U.S. Pat. No. 3,793,512. In the operation of this system, essential or critical components of a machine for manufacturing smokers' products are monitored, and the machine is arrested upon the detection of a malfunction. The interval of time during which the machine is arrested, i.e. while the necessary repairs are made to correct the malfunction, is recorded for subsequent evaluation.
While it is convenient to have a system which automatically shuts down the machine in the event of a malfunction, so that possible damage or waste of raw materials can be avoided, it will be appreciated that any interruption of a high speed manufacturing machine is costly in terms of lost production. Furthermore, the necessary down time of the machine to perform required repairs is lengthened because of its complexity and the need for specialized training. More particularly, a large number of filter rod making machines are typically employed by one manufacturer of smokers' products. Each machine, or a group of a small number of machines, will typically have an operator who is responsible for the start-up of the machine and the proper supply of necessary raw materials such as plasticizer and tow. This person is generally not qualified to repair the machine if a malfunction occurs. Rather, a more skilled person who has served a 3-5 year apprenticeship is responsible for maintaining all of the machines in working order Because the skilled repair person could be in charge of several machines, it could take a considerable period of time before he is able to repair a malfunction at any particular machine.
In the past, other control systems have been used to monitor the final product and automatically regulate the operation of isolated aspects of the machine. In one exemplary system, the weight or density of the cigarette filter rod is monitored and used to control the feed rate of the tow or the rate of application of the plasticizer. While these types of systems have helped to increase the quality or yield of the final product, they do not provide the operator with the type of diagnostic tool necessary to identify machine errors and shorten costly down time or avoid waste of materials. For example, quite frequently the supply of plasticizer runs out before the operator realizes that a reservoir needs refilling. During the time that the reservoir is empty, the machine can continue to run and significant amounts of tow and wrapping paper will be wasted since the resultant products are defective and cannot be recycled.
Accordingly, it is an object of the present invention to provide a system that monitors the operation of the machine and alerts the operator to the occurrence of a condition that could lead to a malfunction. By providing an early warning of these conditions, such a system would enable the operator to take corrective action as well as reduce the waste of expensive raw materials.
It is another object of the invention to provide a novel monitoring system that affords an operator with an integrated overview of all vital machine functions. Further along these lines, it is an object of the invention to provide such a system which presents diagnostic information to an operator so that the cause of a possible malfunction can be given attention before machine shutdown is required.
It is a further object of the present invention to provide a system of this type that also facilitates the automatic correction or control of possible error conditions.